A System for Applying a Masking Material to a Substrate

ABSTRACT

Systems for applying a masking material to a substrate, the system comprising: a source feed for delivering a quantity of masking material to a substrate, a waste deposit for receiving masking material when removed from the substrate, a spray nozzle moveable relative to the substrate and a controller for controlling movement of the nozzle relative to the substrate and the speed of delivery of the masking material from the source feed, wherein the speed of movement of the spray nozzle relative to the substrate is substantially equal to the speed of delivery of the masking material from the source feed.

FIELD

The present invention relates to a system for applying a maskingmaterial to a substrate particularly, but not exclusively for, a paintor print based application.

BACKGROUND

Many everyday objects such as automotive body panels, householdappliances and children's toys are painted or printed by way of a spraybased system. A typical spray based system comprises a nozzle that isco-operable with a reservoir containing a paint medium. A pump is usedto drive the paint medium from the reservoir along a conduit to thenozzle where the paint is applied to a substrate. In most modern sprayprint systems, the position of the nozzle is accurately controlled by acomputer based control system. The position of the nozzle can beadjusted through x, y, z co-ordinates and is typically accurate towithin a very tight tolerance.

The paint medium in the reservoir is configured according toapplication. In an application where a smooth edge is required, thespatial configuration of the paint medium is such that the finish ishomogenous. This is advantageous in most applications but the finishquality can be somewhat diminished where a sharp edge finish isrequired. To produce such a sharp edge finish, it is common for masktape to be applied to the substrate. The substrate is then painted alongwith the mask tape. When the mask tape is removed a sharp edge finish isleft behind on the substrate. This simple process has been used for manyyears but has certain drawbacks including: excess usage of paint,contamination of mask tape by paint, environmental concerns, potentialdamage to the paint finish when the mask tape is removed and cost ofsupplying the mask tape together with the labour required to apply themask tape and remove after painting. In particular, as the used masktape is contaminated with paint it cannot be re-used and it has to bedisposed of into general landfill due to paint contamination. Used masktape cannot be recycled.

The present invention seeks to address the aforementioned problems.

SUMMARY

According to an aspect of the invention, there is provided a system forapplying a masking material to a substrate, the system comprising: asource feed for delivering a quantity of masking material to asubstrate, a waste deposit for receiving masking material when removedfrom the substrate, a spray nozzle moveable relative to the substrateand a controller for controlling movement of the nozzle relative to thesubstrate and the speed of delivery of the masking material from thesource feed, wherein the speed of movement of the spray nozzle relativeto the substrate is configured to be substantially equal to the speed ofdelivery of the masking material from the source feed.

The described system removes the need for by-hand preparation of asubstrate prior to painting thus saving significant time and expense.Furthermore, local environmental contamination is reduced as the maskingmaterial is sent straight to a waste deposit during the painting processand subsequently discarded at the end of the printing operation. Paintdamage is also minimised as the masking material is removed from thesubstrate during the printing operation before the paint is dry. Once aroll of masking material is installed into the source feed, the maskingoperation is automated until such a time that the roll of maskingmaterial is depleted. At that time, a user simply has to dispose of themasking material in the waste deposit and install a new roll of maskingmaterial. This configuration enables the masking system to be used formultiple print operations between installation of new rolls of maskingmaterial.

The source feed, waste deposit and nozzle may define a spray unitmoveable as a single unit.

Advantageously, movement of the source feed, waste deposit and roller asa single unit enables ease of alignment of the masking material with thenozzle during the painting operation.

The source feed may be in the form of a roller. The waste deposit may bein the form of a roller.

Use of a roller for the source feed and the waste deposit ensures thatthe speed at which the masking material leaves the source feed is equalto the speed at which the masking material arrives at the waste deposit.The risk of mechanical failure of either the source feed or the wastedeposit is minimised due to the simple mechanical construction thereof.

The system may further comprise a guide for guiding the masking materialbetween the source feed and the waste deposit.

Use of a guide ensures that the masking material is applied to thesubstrate in the desired manner without twisting or creasing.

The guide may be in the form of a pair of rollers between which themasking material passes.

The masking material may be a paper or plastic based material.

According to another aspect of the invention, there is provided a systemfor applying a masking material to a substrate, the system comprising: asource feed for delivering a continuous loop of masking material to asubstrate, a spray nozzle moveable relative to the substrate forapplying a paint medium to the substrate and a cleaner arranged to cleanexcess paint medium from the masking material.

Use of a continuous loop of masking material that passes through acleaner has a significant positive environmental impact by removing theneed to use non-recyclable paper based masking material that iscontaminated with paint. Passing the continuous loop of masking materialthrough a cleaner enables paint medium to be removed from the maskingmaterial such that the masking material is suitable for extended usewithout requiring replacement.

The speed of movement of the nozzle relative to the substrate may beequal to the speed of delivery of the masking material to the substrate.

The system may further comprise a guide for facilitating delivery of themasking material to the substrate.

The provision of a guide advantageously ensures that the maskingmaterial is applied to the substrate in the desired manner withouttwisting or creasing.

The guide may comprise a pair of rollers spaced apart to contact eitherside of the masking material.

The pair of rollers may be driven by a motor.

Use of a motor to drive the rollers enables the system to urge themasking material against the substrate thus deforming the maskingmaterial and more efficiently masking the surface and preventing paintmedium from getting under the masking material. In combination withspring-like properties of the masking material, the motor provides thatgeometrical inaccuracies can be nullified by urging of the maskingmaterial against the substrate by the motor.

The system may further comprise angular adjustment means for modifyingthe angle of the source feed relative to the substrate.

The use of angular adjustment means provides that the masking materialcan be applied to the substrate in any orientation relative to the pathof the nozzle.

The angular adjustment means may be configured to adjust the angle ofthe masking material such that the masking material is always applied tothe substrate along the direction of travel of the nozzle.

To mask the substrate during painting in a curved direction the angularadjustment means can be configured such that the masking material isalways applied to the substrate in the direction of travel of thenozzle. This also provides the further benefit of a higher quality paintfinish in regions of the substrate where the nozzle follows a curvedpath.

The angular adjustment means may comprise a motor.

Use of a motor enables the angular adjustment means to respond quicklyand in cooperation with a variation in the direction of travel of thenozzle.

The continuous loop of masking material may be formed from a plastic ormetal material.

Use of a plastic or metal material enables the masking material to becleaned without significant risk of damage to the masking material. Aresilient material is important so that it is suitable for prolonged usewithout replacement.

The cleaner may comprise a reservoir and one or more wiping blades.

Provision of a reservoir enables collected paint medium to be stored fordisposal or later re-use or the collected paint medium can be re-usedduring the current printing operation. Use of wiping blades efficientlyremoves wet paint medium from the masking material and causes the paintmedium removed to pool in the reservoir.

The drain may comprise a drain for removal of paint material from thereservoir.

Provision of a drain enables paint within the reservoir to be easilyremoved from the reservoir and disposed of or fed back into the mainprint medium source.

The drain may comprise a valve having a closed position in which paintmaterial cannot exit the reservoir and an open position in which paintmaterial can exit the reservoir through the drain.

Provision of a valve enables a user to manually select when paint mediumwithin the reservoir should be removed therefrom.

The reservoir may comprise a level sensor for detecting the level ofpaint medium within the reservoir and the valve may be controllable by acontroller such that when the level of the paint medium within thereservoir is detected to have reached a pre-determined level by thelevel sensor the valve is moved to the open position to permit paintmedium within the reservoir to drain therefrom.

The system may further comprise height adjustment means for adjustingthe position of the continuous loop of masking material relative to thesubstrate in the y-dimension.

In some applications it may be advantageous for the masking material tobe spaced apart from the substrate to be painted, i.e. the maskingmaterial defines a non-contact mask. This is particularly the case whena finished edge is not required to be sharp such as when painting theinternal surface of a pattern.

The system may comprise two loops of continuous masking material,wherein the two loops are positioned on respective opposite sides of thenozzle.

An arrangement of two loops of masking material enables a paint systemto accurately and efficiently spray paint a line or other narrow featureonto a substrate.

The two loops of continuous masking material may be delivered by acommon source feed.

Each loop of continuous masking material may be delivered by respectivesource feeds.

FIGURES

The invention will now be described by way of reference to the followingfigures.

FIG. 1 illustrates a prior art method of spray painting a substrate;

FIG. 2 illustrates a system for applying a masking material to asubstrate according to a first aspect of the invention;

FIG. 3 illustrates a system for applying a masking material to asubstrate according to a second embodiment of the invention;

FIG. 4 illustrates a variation of the system of FIG. 3 that comprises anangle setting motor to enable the system to be used with curvedsurfaces;

FIG. 5 illustrates another variation of the system of FIG. 3 that doesnot bring the masking material into contact with the substrate;

FIG. 6 illustrates another variation of the system of FIG. 3 that isarranged either side of the nozzle.

DESCRIPTION

A prior art paint spray system 10 is illustrated in FIG. 1. A nozzle 12is arranged such that it is spaced apart from a substrate 14 to bepainted. Masking material 16 is applied to the substrate 14 such thatwhen paint is applied a sharp edge finish is possible. The maskingmaterial 16 is removed from the substrate following completion of thepainting process. The masking material 16 is disposed of into generallandfill due to being contaminated with paint thus preventing recycling.

A first aspect of the invention 100 is illustrated in FIG. 2. A sprayunit 102 is arranged such that it is spaced apart from a substrate 104to be painted. The spray unit comprises a nozzle 106, a source feed 108for dispensing a masking material 110, a waste deposit 112 for receivingused masking material 110 and a guide 114 for guiding the maskingmaterial 110 between the source feed and the waste deposit 112.

The source feed 108 and the waste deposit 112 are shown as rollers inthe embodiment illustrated in FIG. 2. The masking material 110 is fedfrom the source feed 108 and applied to the substrate immediately beforepainting. Following painting, the masking material 110 is removed fromthe substrate 104 and stored in or on the waste disposal 112. One, orboth, of the source feed 108 and waste deposit 112 rollers are driven bymotors.

The spray unit 102 is controlled by a controller 116 which is operableto control the linear movement of the spray unit 102 and transfer of themasking material 110 from the source feed 108 to the waste deposit 112.To facilitate effective operation of the spray unit 102, the controller116 is configured such that the speed of transfer V₁ of the maskingmaterial 110 from the source feed 108 to the waste deposit 112 is equalto the speed of movement V₂ of the spray unit 102 relative to thesubstrate 104. As one or both of the source feed 108 and waste deposit112 rollers are controllable by motor, the speed of the motors can becontrolled as appropriate

A second aspect of the invention 200 is illustrated in FIG. 3. A sprayunit 202 comprises a nozzle 203, a roller 204 around which a continuousloop of masking material 206 is positioned. The masking material 206 istensioned by one or more guides 208. A cleaning box 210 is provided incontact with the masking material 206. The cleaning box 210 comprises awiper 212 for wiping paint medium from the masking material 206. Thepaint medium is collected in a reservoir 214 that is either part of thecleaning box 210 or external to the cleaning box 210. The reservoir 216comprises a drain 220 to enable paint material within the reservoir 214to be drained. The drain 220 comprises a valve 222 that has an openposition in which paint material cannot be removed drained from thereservoir 214 and an open position in which paint material can bedrained from the reservoir 214 through the drain 220.

To tension the continuous loop of masking material, a second roller (notshown) can be provided in-line with the first roller 204. Both the firstroller 204 and second roller, if present, are offset from the nozzle206.

The spray unit 202 is controlled by a controller 216 which is operableto control the movement of the spray unit 202 relative to the substrate218 and movement of the continuous loop of masking material 206 around alooped path. To facilitate effective operation of the spray unit 202,the controller is configured such that the speed of movement V₁ of themasking material 206 around the path is equal to the linear movement V₂of the spray unit 202.

In use, the continuous loop of masking material 206 is positionedagainst or close to a substrate 218 to be painted. As the spray unit 202moves relative to the substrate 218, the masking material 206 movesaround a pre-determined path. The masking material prevents paint mediumfrom being applied to certain areas of the substrate 218.

FIG. 4 illustrates a spray unit 202 that further comprises an anglesetting motor 224. The angle setting motor 224 enables axial rotationaround a y-axis such that the angle of the first roller 204 can beadjusted. In one embodiment, the angle of the first roller 204 iscontrolled by the controller 216 such that angle setting motor 224 isinstructed to adjust the angle of the first roller 204 in accordancewith a change of direction of travel of the nozzle 203.

FIG. 5 illustrates a spray unit 202 that is configured such that themasking material 206 is not in contact with the substrate 218 duringuse. In this example, the masking material 206 is offset a distance xfrom the substrate 218. The first roller 204 is adjustable such that thedistance of the first roller 204 relative to the substrate 218 isadjustable in height.

FIG. 6 illustrates a spray unit 202 that enables two continuous loops ofmasking material 206 to be applied against or close to the substrate218. This can be achieved either through a roller design that canaccommodate two loops of masking material 206. or through provision oftwo sets of rollers with each set of rollers accommodating respectiveloops of masking material 206. Each continuous loop of masking material206 is delivered to the substrate 218 such that the nozzle 203 ispositioned between the two continuous loops of masking material 206 onopposite sides of the nozzle 203.

The aforementioned description is intended to describe an embodiment ofthe invention and is given as an example only.

1.-26. (canceled)
 27. A system for applying a paint medium to asubstrate using a masking material, the system comprising: a source feedfor delivering a quantity of masking material close to the substrate, awaste deposit for receiving the masking material when removed from thesubstrate, a spray nozzle moveable relative to the substrate forapplying the paint medium to the substrate, a cleaner arranged to cleanexcess paint medium from the masking material, and a controller forcontrolling movement of the spray nozzle relative to the substrate andthe speed of delivery of the masking material close to the substratefrom the source feed, wherein the speed of movement of the spray nozzlerelative to the substrate is substantially equal to the speed ofdelivery of the masking material from the source feed.
 28. The systemaccording to claim 27, further comprising a spray unit defined at leastin part by the source feed, waste deposit and spray nozzle, wherein thespray unit is controlled by the controller to be moveable relative tothe substrate as a single unit.
 29. The system according to claim 27,wherein the source feed comprises a roller.
 30. The system according toclaim 27, wherein the waste deposit comprises a roller.
 31. The systemaccording to claim 27, further comprising a guide for facilitatingtransfer of the masking material from the source feed to the wastedeposit.
 32. The system according to claim 31, wherein the guidecomprises a pair of rollers spaced apart to contact either side of themasking material.
 33. The system according to claim 32, wherein the pairof rollers is biased in an engaged position to contact the maskingmaterial and is moveable out of the engaged position to facilitateloading of the masking material.
 34. The system according to claim 31,wherein the guide comprises at least two pairs of rollers, wherein afirst pair of rollers is arranged between the source feed and the spraynozzle and a second pair of rollers is arranged between the spray nozzleand the waste deposit.
 35. The system according to claim 27, furthercomprising angular adjustment means for modifying the angle of thesource feed relative to the substrate.
 36. The system according to claim27, wherein the cleaner comprises a reservoir and at least one or morewiping blades.
 37. The system according to claim 36, wherein the cleanerfurther comprises a drain for removal of paint material from thereservoir, wherein the drain comprises a valve having a closed positionin which paint material cannot exit the reservoir and an open positionin which paint material can exit the reservoir through the drain. 38.The system according to claim 27, wherein the source feed comprises tworollers, each roller driving a respective continuous loop of maskingmaterial, wherein each continuous loop of masking material is configuredto be applied to the substrate, one on each of opposite sides of thenozzle.
 39. The system according to claim 27, wherein the source feedcomprises a roller configured to accommodate two respective continuousloops of masking material space apart to define a gap therebetweenwithin which the nozzle is positioned, in use.
 40. The system accordingto claim 38, wherein the source feed is configured to deliver thecontinuous loop of masking material such that it is spaced apart fromthe substrate by a distance y.
 41. The system according to claim 39,wherein the source feed is configured to deliver the continuous loop ofmasking material such that it is spaced apart from the substrate by adistance y.
 42. The system according to claim 36, wherein the cleanercomprises a level sensor for detecting the level of paint medium withinthe reservoir and the valve is controllable by the controller such thatwhen the level of the paint medium within the reservoir is detected tohave reached a pre-determined level by the level sensor the valve ismoved to the open position to permit paint medium within the reservoirto drain therefrom.